combine 1/2 of marinate in a large zip lock bag. add shanks. massage, flip and coat shanks well. refrigerate over night.
preheat oven to 325 degrees. place shanks on a large oven roasted pan. pour reserved marinate over roast and tent with aluminum foil. bake for 4 hours. baste during the baking time...add a little water to pan jucies while basting. the last 30 minutes un-tent and allow skins to crisp up. shanks are done when juices run clear and meat is tender. allow to rest before slicing.